Novel mutations in NEB cause abnormal nebulin expression and markedly impaired muscle force generation in severe nemaline myopathy. Skelet Muscle 2011 Jun 20;1(1):23
Date
07/30/2011Pubmed ID
21798101Pubmed Central ID
PMC3156646DOI
10.1186/2044-5040-1-23Scopus ID
2-s2.0-84861231735 (requires institutional sign-in at Scopus site) 51 CitationsAbstract
BACKGROUND: Nemaline myopathy (NM) is a congenital muscle disease associated with weakness and the presence of nemaline bodies (rods) in muscle fibers. Mutations in seven genes have been associated with NM, but the most commonly mutated gene is nebulin (NEB), which is thought to account for roughly 50% of cases.
RESULTS: We describe two siblings with severe NM, arthrogryposis and neonatal death caused by two novel NEB mutations: a point mutation in intron 13 and a frameshift mutation in exon 81. Levels of detectable nebulin protein were significantly lower than those in normal control muscle biopsies or those from patients with less severe NM due to deletion of NEB exon 55. Mechanical studies of skinned myofibers revealed marked impairment of force development, with an increase in tension cost.
CONCLUSIONS: Our findings demonstrate that the mechanical phenotype of severe NM is the consequence of mutations that severely reduce nebulin protein levels and suggest that the level of nebulin expression may correlate with the severity of disease.
